For the angels, I took away their aura (mainly because I forgot about it and realised it too late) and took away their ability to move and not trigger AoO. They still could move half their speed as part of Reaping Scythe.
I haven't run the Shadowfell Planar room yet, but here are some general things I used:
* Make the portal behind the door black and opaque, identify it's a portal if they roll.
* To stop people being half-arsed, I had if you poke something through part of the way, it goes all the way in. You poke with a ten foot pole, the pole gets pulled. You stick your head in, you get pulled in.
* The portal goes to the same location for one round. Players can enter the same place together as long as they enter the same round. If one player leaves and comes back, roll again. If players keep entering and exiting, keep rolling.
I'm using the plane shifting rooms as a continuing theme, actually, you might see an earlier post in this thread I did in the "between section" I am running now where the room shifts around the players unless they are standing in the wrong spot, where they get stuck until the merry goround comes around again.
With the clock, I'll have to make it that it can't be solved without seeing the brazier. Maybe the thing is spinning so fast that if they stand in the right spot the shaow will spin around.